My bets going back to November 09

[SPX]

Re: My bets going back to November 09

I appreciate both you guys trying to help me understand . . . but perhaps I should clarify that I am absolutely terrible at math and my mind shuts down as soon as I see numbers. In terms of gambling, it's actually the one area where I am completely lacking.

[MMA_scientist]

Re: My bets going back to November 09

Hey guys, new here. Just checking out the place on Scientist's rec.

Does anyone know how to calculate mathmatical edge? I am math deficient... is it as simple as 82% - 70% = 12% edge? That would be awesome and impossibly huge edge...

For a normal betting event, edge is usually defined as (Win %) / (Implied Win %) - 1. [Equivalently: Win prob * decimal odds -1] In this case, 0.82 / 0.70 - 1 = 0.171, so just over a 17% edge.

However, I am not sure how well this concept is applied to a long string of bets made with different odds. For example, I don't know exactly how you calculated your "average line", but at a minimum, you would want to be averaging the implied probabilities, not the moneyline odds or the decimal odds.

Awesome, thank you so much.

I calculated my average line by adding up all the lines and then dividing them by the number of fights... The average implied probabilty would be about 70% (-233 is 69.93% implied probability if I am not mistaken). Is that wrong? I do math at about the 4th grade level so anything I do is extremely rudimentary.

Also, come back to my blog (I mean private community). You are the only poster that I did not have contact info for. I sent you a PM

[Svino]

Re: My bets going back to November 09

I calculated my average line by adding up all the lines and then dividing them by the number of fights... The average implied probabilty would be about 70% (-233 is 69.93% implied probability if I am not mistaken). Is that wrong?

Unfortunately, yes. Moneyline odds were never meant to be averaged like that. You would have to use the implied probability odds for each fight individually.

Simple example: Suppose you bet on a bunch of fights at 50% odds (-100 moneyline) and an equal number of fights at 90% odds (-900 moneyline). In this case, you should expect to win 70% of the fights (50%+90% / 2). However if you average the moneyline odds, you get (-100 - 900) / 2 = -500, which converts to a probability of 83%. So basically, you'll get the wrong answer, and it can get even uglier if you try to average together favorites and underdogs. Notice that I could have just as easily used +100 and -900, to get a different (and also wrong) average of -400 -> 80%.

[triathlete]

Re: My bets going back to November 09

So the moral of this is to always work in percentages, not lines? This is good info. . . I'm assuming that by working in percentages you can cover the entire range - favs and dogs?

[Svino]

Re: My bets going back to November 09

So the moral of this is to always work in percentages, not lines? This is good info. . . I'm assuming that by working in percentages you can cover the entire range - favs and dogs?

Yeah. If you are writing a computer program (as I think you indicated you were) that is going to take moneyline odds as an input, you need to do something like an if/then/else to handle the favorites and underdogs separately, since they're two different formulas. Then depending on exactly what you're doing, you probably want to either convert to percent odds, or decimal odds (which are 1 / percent odds). For straight averaging as discussed above, you want percent odds.

[MMA_scientist]

Re: My bets going back to November 09

Yeah. If you are writing a computer program (as I think you indicated you were) that is going to take moneyline odds as an input, you need to do something like an if/then/else to handle the favorites and underdogs separately, since they're two different formulas. Then depending on exactly what you're doing, you probably want to either convert to percent odds, or decimal odds (which are 1 / percent odds). For straight averaging as discussed above, you want percent odds.

"Check out the big brains on Brad."

Out of curiosity, what is your background?

[Ludo]

Re: My bets going back to November 09

You can't tell? He's the guy that movie "Good Will Hunting" was based off of. But seriously, thats some pretty interesting stuff. Where did you learn all that?

[Svino]

Re: My bets going back to November 09

My background is in physics. Also, I was raised by mathematicians, which is a little like the academic version of being "raised by wolves".

[MMA_scientist]

Re: My bets going back to November 09

My background is in physics. Also, I was raised by mathematicians, which is a little like the academic version of being "raised by wolves".

That is crazy. This conversation is about as close to physics or mathmatics as I ever get. And honestly, it is hard for me. I feel like I should relinquish my user name and fall on my sword in shame.

There is this whole other world of smart people out there...